Everything I''ve read online indicates that I should expect equal or
greater performance from the blktap drivers instead of file access,
unfortunately this isn''t the case on my test machine
- Dual Xeon L5640, dom0 pinned to 1 cpu backed by a netapp nfs mount.
- Dom 0 running a recent checkout (last day or two) from
xen-4.0-testing with the pvops kernel from Jeremy''s testing (2.6.31.13)
- Dom U running 2.6.32.8
Times indicated are from "time bonnie++ -u 1":
file inside the dom0 (mount -o loop):
file inside a vm:
2m40.515s, 2m38.181s, 2m31.788s, 2m34.391s, 2m35.671s
tap:aio inside the dom0 (tapdisk2 -n and then mounting it):
3m23.040s, 3m19.900s, 3m15.406s, 3m15.594s, 3m14.867s
tap:aio inside a vm:
3m54.694s, 3m49.185s, 3m50.864s, 3m57.644s, 4m1.372s
Any thoughts? That''s nearly a 50% performance hit..
Thanks!
- Nathan
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Javier Guerra Giraldez
2010-Jul-23 22:03 UTC
Re: [Xen-users] Performance issue with blktap2?
On Fri, Jul 23, 2010 at 4:59 PM, Nathan March <nathan@gossamer-threads.com> wrote:> Times indicated are from "time bonnie++ -u 1":be sure to select datasets (much) bigger than the sum of RAM available to DomU and Dom0. if not, you''re just comparing cache access, not disk I/O -- Javier _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users